The present invention relates to a bar guiding device in a feeder for feeding machine tools.
Devices having various structures are known which, in feeders for feeding bars in machine tools, allow to keep the bars guided during the intended machining operations. The most common devices consist of a pair of longitudinally superimposed half-shells that are articulated one another and comprise mutually opposite semicylindrical cavities. By means of suitable actuators, the half-shells are actuated between an open position, in order to allow to insert a bar in the cavity of one half-shell, and a closed position, in which the cavities of the two half-shells are mutually integrated so as to form a channel along which the bar is pushed toward the machine tool. In some embodiments, each half-shell is constituted by a plurality of longitudinally aligned sections.
In particular, Italian patent No. 1,266,350 discloses a guiding device composed of a plurality of pairs of sprockets that mesh together and are provided with polygonal peripheral slots that decrease in depth and form passage and guiding openings for a bar that is driven through them.
In known devices of the described type, the advancement of the bars along the guiding channel is provided by means of an appropriately provided pusher (known as bar pusher), which is connected by means of a bridge to an actuation chain, which lies outside the channel. The bridge is constituted by a plate which, during the advancement of the bar pusher, moves between the contiguous edges that delimit the bar guiding channel on the longitudinal opening side.
In order to allow passage of the bridge, the contiguous edges of the channel must be spaced at least by an extent equal to the thickness of the bridge. In this manner, the guiding channel is open longitudinally through a slit that produces internal edges, against which the bar makes sliding contact during machining. However, if the bar has a polygonal cross-section, during its rotation the edges of the bar collide against the inner edges of the cap, causing damaging vibration and intolerable noise.
The aim of the present invention is to provide a guiding device for bars that allows to obviate these shortcomings suffered by known devices.
Within this aim, an object of the present invention is to provide a device that is flexible in use and is suitable to be used in feeders of various design.
This aim and this and other objects that will become better apparent hereinafter are achieved by a bar guiding device in a feeder for feeding a machine tool, composed of two elements that have respective slots and can move with respect to each other between an open position, which allows insertion of a bar between them, and a mutually adjacent position, at which said slots form a longitudinal channel for the advancement of a bar to be fed to the machine tool by means of a bar pusher connected to an actuation chain that is external to said channel by means of a bridge that is guided through regions where said two elements mate, characterized in that said regions are in mutual contact, so as to close said channel, and can undergo elastic deformation in order to allow the passage of said bridge between them.